In a mixer, add margarine, white sugar, eggs, and beat until light and fluffy. Slowly add flour, cream of tartar, baking soda, and salt. Mix well and chill in refrigerator overnight. Roll in balls the size of a walnut. In another container put 2 TBSP of white sugar and 2 tsp. cinnamon. Mix with a spoon. Roll each ball in the sugar/cinnamon mix. Place balls on greased cookie sheet and bake at 375 degrees about 12 minutes (until slightly brown).